Three-Phase Resonant DC-DC Converter With Clamping Diode Protection
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Solution Overview
Problem
Existing three-phase LLC resonant DC-DC converters require software-based short circuit protection, which can be complex and costly, and also necessitate additional transformers that increase size, mass, and cost.
Innovation Solution
The proposed three-phase resonant DC-DC converter incorporates a transformer device with three primary and three secondary windings, a switching circuit with SC nodes connected to the primary windings, a rectifying circuit with RC nodes connected to the secondary windings, and a resonant tank device with resonant inductors and capacitors. This configuration eliminates the need for software-based short circuit protection by using clamping diodes to protect the primary side resonant capacitors and switches from over-voltages and over-currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If software-based short circuit protection is used, then protection functionality is achieved, but device complexity and cost increase
Solution Approach 1:
Clamping diodes are introduced as intermediary protective elements that automatically limit voltage excursions and protect against short circuits. These diodes act as passive mediators between the resonant capacitors and the switching circuit, eliminating the need for complex software-based protection while maintaining reliability.
Solution Approach 2:
The patent replaces software-based protection control with hardware-based clamping diodes. This substitution moves the protection mechanism from an active software control system to a passive hardware circuit element that automatically protects against short circuits without requiring software intervention.
2Reliability
If additional transformers are added for protection, then reliability improves, but weight and size increase
Solution Approach 1:
The clamping diodes are integrated into the existing converter circuitry, merging the protection function with the main power conversion circuit. This integration allows short circuit protection to be achieved without adding separate transformer components, thereby avoiding the associated weight and size penalties.
3Reliability
If clamping diodes are added to protect resonant capacitors, then reliability improves, but device complexity increases
Solution Approach 1:
Clamping diodes serve as intermediary protective elements that limit voltage excursions across the resonant capacitors. By placing these diodes in parallel with the capacitors, the circuit automatically clamps voltage to safe levels during fault conditions, providing robust protection with minimal additional components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides effective protection against short circuits without relying on software-based methods, reducing complexity and cost, and maintaining the advantages of three-phase LLC resonant converters while minimizing the need for additional transformers.
Implementation Method 1
a resonant tank device comprising a primary side resonant tank device connected between the first SC node, the second SC node and the third SC node of the switching circuit and the primary terminals of the three primary windings of the transformer device
Implementation Method 2
a transformer device comprising three primary windings and three secondary windings
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
The present invention describes a three phase resonant DC-DC converter for converting a first DC voltage between two first terminals to a second DC voltage between two second terminals. The converter comprises a transformer device with three primary windings and three secondary windings, a switching circuit, a rectifying circuit, a resonant tank device, a secondary capacitor, and a control circuit. The resonant tank device has a primary side resonant tank device with three resonant inductors and three resonant capacitors connected to the primary windings. The converter further includes three clamping diodes between each of the second primary terminals of the primary windings and the first positive terminal, and three further clamping diodes between the first negative terminal and each of the second primary terminals of the primary windings.